Mexico's most powerful woman was formally charged with a massive embezzlement scheme on Wednesday, standing grim-faced behind bars live on national television in what many called a clear message that the new government is asserting its authority.

The country watched rapt as national teachers union head Elba Esther Gordillo heard the charges against her read by a judge in a grim prison in eastern Mexico City. It was a dizzying fall from power for a woman who traveled on private jets and maintained properties worth millions of dollars in Southern California.

Gordillo was charged with embezzling about $160 million from union funds, as well as organized crime. The judge in the case said a decision about whether the evidence is sufficient to merit a trial would be taken in three to six days.

If found guilty, Gordillo could face 30 years in prison.

She was arrested Tuesday afternoon as she returned from San Diego for a meeting of leaders of the 1.5 million-member National Union of Education Workers she has led for nearly a quarter-century. She was heading the union's fight with President Enrique Peña Nieto's administration over the country's most sweeping educational reform in more than 70 years.

Her arrest came a day after the president signed the reform into law.

"This is a case that has absolutely no political motivation," Attorney General Jesus Murillo Karam told the Televisa television network.

But most Mexicans scoffed at the idea that prosecutors had just found out that Gordillo - known for her designer clothes, luxury cars and plastic surgery - might be corrupt. Many saw it as a warning to potential foes by the Institutional Revolutionary Party, or PRI, which ran the country for seven decades, was thrown out of power in 2006 and won back the presidency last year.

"The message is that, if this can happen to Elba Esther, it can happen to anyone," former Mexico City Mayor Manuel Camacho Solis told MVS Radio. Prosecutors said they had detected nearly $3 million in purchases at Neiman Marcus stores using union funds, as well as $17,000 in U.S. plastic surgery bills and the purchase of a million-dollar home near San Diego.

The arrest immediately sparked calls for prosecutors to bring similar cases against other union leaders known for lavish spending. The main opposition parties specifically named the leader of the country's oil workers' union, accused by local news media of giving his son a $2 million Ferrari, a report that has never been confirmed or denied.

The arrest of Gordillo sidelines a powerful opponent of the PRI even as the administration takes on a figure many blame for the dire state of the Mexican education system. Gordillo was a PRI leader for decades before splitting from the party, which was accused of corruption and authoritarian practices during its decades in power.

"This can be something very good for the country, but also for the government and for the PRI," said Jose Antonio Crespo, a political analyst at the Center for Economic Research and Teaching in Mexico City. "It cleans up the image of the PRI, as if to say, "Yes, we will be a different PRI, we're moving forward, not backward."

The Mexican education system has been persistently one of the worst performers among the world's developed economies, with few signs of improvement.